A group of retired Taiwanese generals on Friday left for China on a controversial trip aimed at building confidence between the two militaries.

Retired general Hsu Li-nung was quoted by the Central News Agency as saying that the group hoped to help avoid conflicts by promoting the establishment of a so-called military mutual trust mechanism.

"The (Taiwan) government has said the timing is not ripe for the mechanism so it is up to the civilian sector to get in touch, otherwise the timing will never be ripe," said Hsu, leader of the group.

The group is scheduled to visit a People's Liberation Army unit in Beijing, attend a forum at a PLA university and meet with top Chinese military and political officials in a week-long visit, the report said.

Taiwan's defence ministry said in a statement that it had not authorised the group to discuss military confidence-building with China.

China still regards Taiwan as part of its territory awaiting reunification, by force if necessary, even though the island has been self-governed since they split in 1949 after a civil war.